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View Full Version : What type of knurl to get



jmh
07-29-2006, 07:43 PM
Hello group:

I'm just going to start getting into knurling. I see in the tool catalogues that there are left hand and right hand spiral knurls, and also diamond knurls. I realize the diamond knurls will make a diamond pattern. However will a left hand and a right spiral knurl used together (on a scissors knurler) not do the same thing, or is there some difference that I'm missing? I'm looking at the FormRol brand of knurls and they call them spiral knurls instead of diagonal knurls, as other companies do.

I'm also going to use diametral pitch knurls in order to keep things simple as to sizing the knurl to the work piece diameter.

See, I told you I was just getting started. I hope these questions aren't too dumb. Thanks in advance.

John

TGTool
07-29-2006, 11:20 PM
John,

Yes, a left and right hand cutter are used together in the knurling tool to make the diamond pattern.

I've (almost) always had good luck without paying much attention to the theoretically correct size for the knurling cutter pitch. Crank some pressure in before you start and the knurls will usually fall into synch.

I've also done straight knurling with one of the diamond cutting wheels by mounting it alone, then rotating it so the grooves are straight where it contacts the work. Because of the way the wheel approaches and retreats as it rotates it will do more of a cutting action. FWIW

Jan

SGW
07-30-2006, 08:12 AM
I've always used a left/right spiral pair to produce diamond knurling. Based purely on speculation, it seems to me as though they may require less force than a diamond knurl...but that may be totally incorrect.

Like TGTool, I wouldn't worry too much about the theoretically correct diameter business.

RobDee
07-30-2006, 08:16 AM
Also if you have a light lathe use a scissor knurl. Knurls exert a good amount of force on crossfeeds.

Rob Dee

nheng
07-30-2006, 08:32 AM
Even on a larger lathe, a scissor type knurl prevents small diameter parts from deflecting from the knurling force. Den

BadDog
07-30-2006, 12:30 PM
Enco sells a somewhat decent scissor knurl holder, I have one. Or you can make your own (http://homepage2.nifty.com/mini-lathe/knurl2/knurl-2-e.htm) like that Japanese fellow.

Fred White
07-30-2006, 02:28 PM
>>The holder should be angled three to five degrees on the left.

Is that true?

dicks42000
07-30-2006, 02:49 PM
As mentioned by a couple of others, a good scissor knurling tool is the only way to knurl on slender work, or on a light lathe (like the Atlas 618), with out fiddling around setting up the follow rest.
Don't ask how I know this...
Rick

BadDog
07-30-2006, 02:54 PM
>>The holder should be angled three to five degrees on the left.

Is that true?
I suppose it would work for a single roller knurl tool. But for a double or scissor, you wouldn't get full width contact. I would imagine that would just be a PIA to get a clean knurl, particularly in steel, but that’s just a guess. And it might even damage the scissor type with the non-oriented loads (twisting) that would be created. I’ll be keeping mine vertical unless I see some compelling evidence to the contrary...

ulav8r
07-31-2006, 12:12 PM
There is a difference. The left and right angled knurls used together will leave a raised diamond on the workpiece. A diamond knurl will leave an impressed diamond in the workpiece. A very different look and feel between the two.

JCHannum
07-31-2006, 12:34 PM
>>The holder should be angled three to five degrees on the left.

Is that true?

That is the way some of the holders on CNC machines are used. The difference is that it produces a cut knurl rather than a rolled knurl. The wheels must have a 90 degree sharp edge, not the angle that is present on some.

sch
07-31-2006, 01:30 PM
Manual knurlers are always set perpendicular to the surface to be knurled and scissors type are advisable for lathes under 2tons in weight. Knurlers forced into the work by the cross slide screw tend to chew up the cross slide screw after a little while. When I was at the adult ed course there were 5-6 ~1/2" acme screws in the scrap box that came off the 14x60 SB lathes. All had chewed up sections the instructor was convinced was caused by using pressure type non scissors knurlers. And student projects didn't invove much knurling, maybe 3-4ft cumulative per year per lathe.

BadDog
07-31-2006, 02:35 PM
There is a difference. The left and right angled knurls used together will leave a raised diamond on the workpiece. A diamond knurl will leave an impressed diamond in the workpiece. A very different look and feel between the two.
Cool, never saw one of those diamond impression knurls. I'll have to keep an eye out...

ulav8r
07-31-2006, 05:19 PM
This is the impressed diamond knurl.-- http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=2098202&PMT4NO=10159383

This is a raised diamond knurl that is different from either one I described.-- http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=2098207&PMT4NO=10159383

BadDog
08-01-2006, 03:02 AM
Interesting, thanks. But I wonder how in the heck you get a consistent pattern with 2 of either. Almost seems you would have to run them alone.